In a typical truck van, a horizontal bed or floor is provided for supporting articles being transported. Articles are placed on this bed, and depending upon the size of the articles, they may be stacked upon each other at two or more levels.
In some instances, it may be impractical to stack the articles due to the weight or configuration. Where this is the case, a substantial amount of the vehicle interior is rendered unusable. For example, where the articles or containers are fragile, damage to the articles will occur if stacked to the extent that the weight of the upper articles would damage lower articles. In those instances, it is often necessary to avoid stacking or to minimize the amount of stacking.
Some articles are also somewhat difficult to handle due to their weight and configuration. This creates problems for the individuals loading the articles on a bed. Thus, even if articles at a lower level will not be damaged when other articles are stacked thereon, stacking itself may be quite cumbersome and inefficient due to the size and weight of the articles.
Attempts have been made to address some of these problems by incorporating intermediate decks in vehicles. Various types of collapsible or removable intermediate deck structures have been proposed for supporting freight articles of various shapes and weights above the horizontal bed or floor of a transport van, and the like, in order to increase the load carrying ability of a van and to maximize the use of the available cubic capacity of a van. The use of collapsible or removable intermediate decks has not met with wide success, however, due to inefficiencies in the design of the decks which make them too complex, too expensive for practical purposes or simply too inconvenient to use.
The design of existing intermediate deck structures often consist of two deck panels, hinge mounted on opposing walls to enable storage of the deck panels vertically against the side walls. The deck panels rotate downwardly or upwardly on the hinges to a horizontal position to form a continuous section of deck, or secondary floor. Typically, this form requires a means of supporting the deck halves horizontally in a manner which both encroaches on additional usable volume for loading the freight or cargo, and interferes with that space requiring extra effort and time to load around it. Such supports include cantilever support structures, suspension chains or cables or even vertical support legs extending to the primary floor.
For example, U.S. Pat. No. 3,911,832 to Vandergriff discloses an intermediate deck structure for use in railway cars, truck and trailer vans. The deck structure includes a first section pivotally connected at its outer end to the side wall of a vehicle, and adapted to be pivoted between a stored position adjacent the side wall and a horizontal position with its inner end extending inwardly from the side wall. A second section of the Vandergriff intermediate deck has a pair of arms extended from its inner end which are pivotally connected to the first section at a point between the inner and outer ends. The second section of the intermediate deck is adapted to be stored adjacent the side wall of the vehicle below the first section of the intermediate deck in a position extending downwardly from the outer end of the stored first section. The second section is adapted to be pivoted relative to the first section during pivoting of the first section to a horizontal loading position, whereby the second section can also be moved to a horizontal loading position with the outer end of the second section supported by a pair of load brackets engaged with a load rail on the opposite side wall of the vehicle.
A problem encountered with the intermediate deck structure of Vandergriff is that the individual deck structures do not lock together when the two deck sections are stored against the side wall of the vehicle, and the load bracket on the second section extends downwardly to a position where it can interfere with and damage cargo and boxes sitting on the main floor of the vehicle. A further problem with the Vandergriff deck is that the load brackets employed in the intermediate deck structure are subject to jumping out of the wall load track rail slots, causing the load brackets to retract under a load on the deck, and dropping the load onto the cargo positioned underneath the intermediate deck.
U.S. Pat. No. 5,452,972 to Adams discloses a deck structure for use in supporting cargo at an intermediate level above the floor or bed of a trailer van. The Adams intermediate deck includes a first deck section pivotally mounted on a side wall of a trailer van and movable to a horizontal load position, and back up to a vertical stored position against the side wall. Adams employs a complex spring slam bolt and release chain system engaged with a height saving angle locking rail to releaseably hold the deck section. A second section of the deck is pivotally connected to the first section and it is also movable between a horizontal load position and a vertical stored position against the side wall. When the second section is in the vertical stored position it is hanging from the first section and is configured such that it nests in the first deck section to provide a storing intermediate deck structure. When the first and second deck sections are in a horizontal load position, the second section has an outer end which is selectively provided with either the spring biased, telescopically mounted load bracket, or a cap style load bracket, that is operatively seated on a load track rail on the trailer van wall opposite to the wall on which the first deck section is hinged. Although the intermediate deck structure of Adams addresses some of the problems of Vandergriff, in doing so it employs complex chain and spring systems that increase the expense of the intermediate deck structure and enhance the risk of injury to the operator of the system. Also, like Vandergriff, Adams fails to address the problem of the lack of structure to lock individual deck structures together.
U.S. Pat. No. 3,875,871 to Thorton discloses a freight carrier such as a railroad car having sections which, unlike the structures in Vandergriff or Adams, fold from opposite walls toward one another from a stored position to an operational position. In the installed position the sections provide a supplementary cargo level. According to Thorton, in this position the sections have joining means which self-support the load and transmit lading shearing and bending moments between the sections so that additional supports from the floor are not required. The deck sections of the Thorton carrier are provided with flanges or blocks for supporting the sections when they are unfolded and for providing a resting space for subsequently lowered sections. Thorton also describes permanent support areas positioned at one end of the freight car designed to provide a resting area for the first lowered panels. The patent describes these rest areas as a bracket or ledge mounted on the rear wall of the carrier by suitable fasteners or welding.
Other U.S. patents showing related structures include U.S. Pat. Nos. 4,281,870; 3,897,971; and 5,375,534.
Although Thorton seemingly overcomes many of the problems of Vandergriff and the complexities of Adams, it requires welding structures or fasteners to the interior portion of the carrier to do so. Moreover, although Thorton provides flanges or blocks for supporting subsequent sections, the panels described in Thorton are vulnerable to sag under heavier loads due to inadequate support. Moreover, the flanges or blocks of Thorton subject the panels to interference with one another and, like Vandergriff and Adams, do not interlock the panels together in the operational position. Another problem encountered with such systems is stress placed on attachment and hinge systems by flexing of trailer side walls, for example while the vehicle is travelling on the road. Furthermore, in some systems a hinge utilized for deploying and stowing an intermediate deck may have to bear the full weight of the items loaded on the intermediate deck.
Consequently, there is a need for a system for supporting articles more efficiently for transportation purposes. In particular, there is a need for such a support system that is of a highly efficient design whereby the deck can be economically installed in a vehicle, each individual intermediate deck can be adequately supported and locked together with other intermediate decks, the deck system is not adversely affected by flexing of trailer walls, and the system can be efficiently operated by a single user.